Anthropometric and metabolic factors and risk of benign prostatic hyperplasia: a prospective cohort study of Air Force veterans

Diabetes, growth hormone-insulin-like growth factor pathways and association to benign prostatic hyperplasia

Diabetes significantly increases the risk of benign prostatic hyperplasia (BPH) and low urinary tract symptoms (LUTS). The major endocrine aberration in connection with the metabolic syndrome is hyperinsulinemia. Insulin is an independent risk factor and a promoter of BPH. Insulin resistance may change the risk of BPH through several biological pathways. Hyperinsulinemia stimulates the liver to produce more insulin-like growth factor (IGF), another mitogen and an anti-apoptotic agent which binds insulin receptor/IGF receptor and stimulates prostate growth. The levels of IGFs and IGF binding proteins (IGFBPs) in prostate tissue and in blood are associated with BPH risk, with the regulation of circulating androgen and growth hormone. Stromal-epithelial interactions play a critical role in the development and growth of the prostate gland and BPH. Previously, we have shown that the expression of c-Jun in the fibroblastic stroma can promote secretion of IGF-I, which stimulates prostate epithelial cell proliferation through activating specific target genes. Here, we will review the epidemiologic, clinical, and molecular findings which have evaluated the relation between diabetes and development of BPH.

Lifestyle factors, benign prostatic hyperplasia, and lower urinary tract symptoms

PURPOSE OF REVIEW

Although age, genetics, and sex steroid hormones play prominent roles in the cause of benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS), recent epidemiological studies suggest that modifiable lifestyle factors also contribute substantially to the pathogenesis of these conditions.

RECENT FINDINGS

Lifestyle and metabolic factors associated with significantly increased risks of benign prostatic hyperplasia and lower urinary tract symptoms include obesity, diabetes, and meat and fat consumption. Factors associated with decreased risks include physical activity, moderate alcohol intake, and vegetable consumption. Factors for which no clear risk patterns have emerged include lipids and smoking. Randomized clinical trials of lifestyle alterations - such as weight loss, exercise, and diet - for the prevention or treatment of benign prostatic hyperplasia and lower urinary tract symptoms have yet to be performed.

SUMMARY

Lifestyle factors present a novel opportunity for the prevention and treatment of benign prostatic hyperplasia and lower urinary tract symptoms. Although clinical trials of lifestyle modifications have not yet been undertaken, promotion of healthy lifestyle alternatives within the context of standard benign prostatic hyperplasia and lower urinary tract symptoms treatment algorithms is potentially beneficial.

Benign Prostatic Hyperplasia and Male Lower Urinary Tract Symptoms: Epidemiology and Risk Factors

The epidemiology of benign prostatic hyperplasia (BPH) and male lower urinary tract symptoms (LUTS) has evolved considerably during the past several years. The term LUTS describes a distinct phenotype and allows for a broad epidemiologic description of urinary symptoms at a population level. Although it is becoming the preferred term for studying urinary symptoms in populations, LUTS remains interconnected with BPH in the literature. The incidence and prevalence of BPH and LUTS are increasing rapidly as the US population ages. BPH and LUTS are associated with serious medical morbidities, an increased risk of falls, depression, diminished health-related quality of life, and billions of dollars in annual health care costs. Although age and genetics play important roles in the etiology of BPH and LUTS, recent insights at the population level have revealed that modifiable risk factors are likely key components as well. Serum dihydrotestosterone, obesity, elevated fasting glucose, diabetes, fat and red meat intake, and inflammation increase the risk; vegetables, regular alcohol consumption, exercise, and NSAIDs decrease the risk.

Statin use and decreased risk of benign prostatic enlargement and lower urinary tract symptoms

OBJECTIVE

To determine whether statin use is associated with a decreased risk of developing benign prostatic enlargement (BPE) and lower urinary tract symptoms (LUTS).

SUBJECTS AND METHODS

We conducted a retrospective, population-based cohort study of 2447 men, 40-79 years of age, residing in Olmsted County, MN, USA, in 1990, and followed these men biennially through 2007. Cox proportional hazard models were used to assess associations between statin use and new onset of moderate/severe LUTS (American Urological Association Symptom Index score >7), a decreased maximum urinary flow rate (<12 mL/s) or BPE (prostate volume >30 mL).

RESULTS

Statin use was inversely associated with new onset of LUTS (Hazard ratio (HR) 0.39; 95% confidence interval (CI) 0.31-0.49), a decreased maximum flow rate (HR 0.53; 95% CI 0.34-0.82) and BPE (HR 0.40; 95% CI 0.23-0.69) after adjustment for baseline age and body mass index, diabetes, hypertension, coronary heart disease, smoking, alcohol use, activity level and non-steroidal anti-inflammatory use. The longest duration of statin use was associated with the lowest risk of developing each outcome (all tests for trend: P < 0.001).

CONCLUSION

In this study, statin use was associated with a 6.5- to 7-year delay in the new onset of moderate/severe LUTS or BPE. While men typically take statin medications to prevent coronary heart disease events and related outcomes, these data suggest that men who use statins may also receive urologic benefits.

Effects of obesity on prostate volume and lower urinary tract symptoms in korean men

Purpose

We investigated the effects of obesity on prostate volume (PV) and lower urinary tract symptoms (LUTS) in Korean men.

Materials and Methods

From December 2007 to 2009, a total of 10,383 ostensibly healthy Korean men aged ≥50 years visited our health promotion center for a routine check-up. Among them, 872 men who wanted a prostate evaluation were enrolled in this study. All men underwent detailed clinical evaluations with the International Prostate Symptom Score (IPSS) questionnaire. Anthropometric measurements, including height, weight, and waist and hip circumferences, were determined. A blood sample was obtained for serum prostate-specific antigen (PSA) measurement. Thereafter, a digital rectal examination and transrectal ultrasound were performed.

Results

In total, 465 men with moderate to severe LUTS (IPSS≥8 points) were included in this prospective study. The participants' mean age was 57.2 years. Multivariate analysis demonstrated that only waist circumference was a significant factor in predicting PV besides age and serum PSA. The univariate analysis showed no statistically significant relations between any of the obesity-related parameters and LUTS. The PV was also not correlated with LUTS.

Conclusions

Central obesity is the more important predictor of PV than overall obesity. There are no significant relations between obesity-related parameters and LUTS.

Serum prostate-specific antigen is better correlated to body surface area than body mass index in a population of healthy Korean men

It has been suggested that the larger vascular volume among obese men causes a dilution effect, decreasing the concentration of serum prostate-specific antigen (PSA). However, plasma volume is proportional to body surface area (BSA) rather than to body mass index (BMI). We determined whether serum PSA level is better correlated to BSA than BMI in a population of ostensibly healthy Korean men. Data from 2604 men who visited our health promotion center were evaluated. All men underwent anthropometric measurements, digital rectal examination, serum PSA determination, and transrectal ultrasound examination. The correlation between serum PSA and other parameters was statistically analyzed. The mean age was 49.9 years and the mean serum PSA level was 1.14 ng/mL. The multivariate analysis revealed that the serum PSA was positively correlated with age, prostate volume, and negatively correlated with BSA only and not with BMI. In addition, BSA, rather than BMI, was the significant factor in predicting the prostate volume. Our results suggest that men with larger BSA (rather than BMI), have larger prostate volumes, and lower serum PSA.

Benign prostatic hyperplasia: does lifestyle play a role?

Benign prostatic hyperplasia (BPH) is a very common condition in older men, affecting up to 80% of men aged >or= 80 years in the United States. It typically leads to lower urinary tract symptoms, which often require medical management. The exact cause of BPH is unknown, and the only 2 established factors associated with BPH are age and the presence of androgens. Although the presence of testosterone is required for the development of BPH, testosterone is not thought to be the underlying factor causing BPH because testosterone levels decrease in older men. Recent studies have reported that BPH is associated with elevations in plasma estradiol/testosterone ratio, insulin, and insulin-like growth factor-I. Daily aerobic exercise can reduce all of these plasma factors, particularly when combined with a low-fat, high-fiber diet consisting of whole grains, fruits, and vegetables. In cell culture studies, this type of lifestyle regimen has recently been shown to reduce the growth of serum-stimulated prostate epithelial cells and the growth of androgen-dependent prostate cancer cell lines.

Lower urinary tract symptoms, benign prostatic hyperplasia, and obesity

Obesity has emerged as a global public health challenge. During the past 20 years, there has been a dramatic increase in obesity in the United States. In 2007, only one state had a prevalence of obesity less than 20%. In this growing epidemic of national concern is an emerging relationship between lower urinary tract symptoms (LUTS), benign prostatic hyperplasia (BPH), and obesity. BPH is the most common neoplastic condition afflicting men and constitutes a major factor impacting the health of the American male. Associations among obesity, physical inactivity, and BPH/LUTS resulting from epidemiological studies have not been explored via clinical trial methodology. A review of the available data appears to support a strong independent relationship between obesity and BPH/LUTS. This review also indicates that gene expression within the prostate varies with prostate size and can be affected by lifestyle modifications. Future studies may lead to office detection of a patient's particular polymorphisms, which may help guide individual treatment and lifestyle modifications that are more likely to succeed.

Insulin-like growth factor-I, insulin-like growth factor binding protein-3 and risk of benign prostate hyperplasia in the prostate cancer prevention trial

BACKGROUND

We investigated whether peptides involved in cellular proliferation and apoptosis, [insulin-like growth factor I (IGFI) and its major binding protein (insulin-like growth factor binding protein 3)], predicted risk of benign prostate hyperplasia (BPH).

METHODS

We conducted a nested-case-control study in the placebo arm of the prostate cancer prevention trial (PCPT). Cases (n = 727) were men with surgical or medical treatment for BPH; two or more IPSS scores >14; or two scores of at least five points over baseline one of which was >or=12. Controls (n = 727) were frequency matched by age to cases, reported no BPH treatment, and no IPSS score >8. Cases and controls remained on the PCPT placebo and were followed closely until their 7-year PCPT anniversary. Baseline serum was analyzed for IGFI and IGFBP3. Unconditional logistic regression and polytomous regression estimated the multivariate-adjusted odds ratio (OR) for BPH risk.

RESULTS

IGFBP3 was inversely and the IGFI:IGFBP3 ratio was positively associated with BPH risk, but findings were statistically significant only for men with severe symptoms (OR = 0.60, 95% CI = 0.40-0.90 for the fifth vs. first quintile of IGFBP3, P-trend = 0.01). Associations did not differ by age (<65 or >or=65 years), and there was a suggestion that the IGFI:IGFBP3 - BPH risk association may be stronger among overweight men.

CONCLUSIONS

A high IGFI:IGFBP3 ratio was associated with increased BPH risk, and high serum IGFBP3 was associated with decreased BPH risk among men with severe symptoms. These results confirm findings from other recent studies.

Birth weight, abdominal obesity and the risk of lower urinary tract symptoms in a population based study of Swedish men

PURPOSE

Lower urinary tract symptoms and obesity are prominent health problems. Low birth weight increases the adult risk of adiposity and insulin resistance, which may increase sympathetic activity and potentially lower urinary tract symptoms. Results of obesity and lower urinary tract symptoms studies are conflicting, and low birth weight and lower urinary tract symptoms relationships have not been investigated.

MATERIALS AND METHODS

This cross-sectional study examines lower urinary tract symptoms, body measures, activity, birth weight and lifestyle data collected by questionnaire from 1997 to 1998. Overall 27,858 men were analyzed and odds ratios calculated after excluding those with cancer, cerebrovascular accident, diabetes and incomplete information.

RESULTS

After adjustment for age, activity level, smoking, alcohol, coffee intake and body mass index, a significant positive association was seen between abdominal obesity (waist-to-hip ratio) and moderate to severe lower urinary tract symptoms. The risks of moderate to severe and severe lower urinary tract symptoms were 22% (95% CI 1.09-1.37) and 28% (95% CI 1.01-1.63) higher, respectively, for the top vs the lowest abdominal obesity quartile. The risk of nocturia (twice or more per night) was 1.16 (95% CI 1.02-1.33) in men in the top compared to the bottom waist-to-hip ratio quartile. Men with low birth weight (less than 2,500 gm) had a 61% (95% CI 1.12-2.30) higher risk of severe lower urinary tract symptoms compared to men with normal birth weight (2,500 to 3,999 gm). Men in the top waist-to-hip ratio quartile who had low birth weight had twice the risk of severe lower urinary tract symptoms (95% CI 1.29-3.02) compared to men with normal birth weight and in the lowest waist-to-hip ratio quartile.

CONCLUSIONS

Low birth weight and abdominal adiposity are associated with increased risk of moderate to severe lower urinary tract symptoms in adults. Further investigations are needed to determine if decreases in obesity can ameliorate lower urinary tract symptoms.

Physical activity, benign prostatic hyperplasia, and lower urinary tract symptoms

BACKGROUND

While some studies have indicated that physical activity may protect against benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS), others have not.

OBJECTIVE

To evaluate the association of physical activity with BPH and LUTS.

DESIGN, SETTING, AND PARTICIPANTS

Systematic review and meta-analysis using MEDLINE, the Cochrane Library, EMBASE, and abstracts from the Annual Meeting of the American Urological Association. We selected observational studies that provided empirical data and analyzed abstracted data with random effects models.

MEASUREMENTS

BPH, LUTS, and physical activity levels.

RESULTS AND LIMITATIONS

Eleven (n=43 083 men) studies met selection criteria. Eight studies observed inverse, 2 studies null, and 1 study equivocal associations of physical activity with BPH or LUTS. Eight studies (n=35675) were eligible for pooled analyses. We stratified physical activity levels into light, moderate, and vigorous categories, with a sedentary category for reference. Compared to the sedentary group, the pooled odds ratios for BPH or LUTS were 0.70 (95% CI 0.44-1.13, p=0.14), 0.74 (95% CI 0.60-0.92, p=0.005), and 0.74 (95% CI 0.59-0.92, p=0.006) for men engaging in light, moderate, and heavy physical activity, respectively.

CONCLUSIONS

Physical activity reduces the risks of BPH and LUTS. These findings are consistent with other studies demonstrating that the BPH/LUTS complex is associated with modifiable risk factors of cardiovascular disease and suggest that increased physical activity may prevent or attenuate these conditions.

Lipids, lipoproteins and the risk of benign prostatic hyperplasia in community-dwelling men

OBJECTIVE

To examine the associations of serum lipids and lipoproteins with benign prostatic hyperplasia (BPH) in community-dwelling men.

SUBJECTS AND METHODS

This analysis was conducted within the Rancho Bernardo Study, a prospective, community-based cohort study. BPH was defined as a history of prostate surgery for other than cancer, or a medical diagnosis of BPH. Logistic regression modelling, with adjustments for age and stratification by diabetes diagnosis, was used to estimate the odds ratio (OR) of BPH associated with fasting serum concentrations of total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, and the triglyceride to HDL ratio.

RESULTS

Among 531 eligible participants, 259 (48%) reported BPH and 272 (52%) reported no BPH. Men with BPH, with a mean (range) age of 75.8 (76.1-80.1) years, were older than men without BPH , at 72.7 (72.4-74.0) years. There were no significant associations of total cholesterol (P trend, 0.52), HDL cholesterol (0.56), triglycerides (0.30), or triglyceride to HDL ratio (0.13) with the risk of BPH. In a subset analysis in men with diabetes, those in the highest tertile (>133 mg/dL) of LDL cholesterol, compared with those in the lowest tertile (<110 mg/dL), were four times more likely to have BPH (odds ratio 4.00, 95% confidence interval 1.27-12.63, P trend 0.02). These results were not explained by the use of statins.

CONCLUSIONS

In these community-dwelling men, higher serum LDL was associated with a greater risk of BPH among diabetics. These data suggest that diabetic men with increased LDL cholesterol are at greater risk of BPH. This observation is consistent with the concept that cardiac risk factors are involved with the pathogenesis of BPH.

Metabolic syndrome and prostate cancer

Prostate cancer is a common form of cancer in men and the incidence increases with age. It is known to develop slowly but may also take an aggressive course. No conclusions have been made on the cause of prostate cancer and there is no diagnostic factor that can be used for screening purposes. Studies indicate that metabolic syndrome is associated with prostate cancer. Metabolic syndrome components are hypertension, dyslipidemia, glucose intolerance and obesity. A systematic literature search for studies on metabolic syndrome or insulin resistance and prostate cancer was performed using the OVID database manager searching the Medline and EMBASE databases. Seven studies were included, of which five were prospective cohorts and two were case-control studies. Most other studies were reviews. Four studies showed a positive association, one showed a negative association and one showed no association. One study, using two different analyses for metabolic syndrome, showed a positive association, or none, depending on the criteria used for defining metabolic syndrome. The results indicate that metabolic syndrome can be used to identify men at risk of prostate cancer. The definition of the metabolic syndrome must be taken into consideration.

Beyond the lower urinary tract: the association of urologic and sexual symptoms with common illnesses

OBJECTIVE

In addition to being prevalent and bothersome, urologic and sexual symptoms may be related to chronic medical illnesses. We investigate the relationship between ten urologic and sexual symptoms and four major illnesses (type II diabetes, cardiac disease, hypertension, and depression).

METHODS

We analyzed data from the Boston Area Community Health (BACH) survey, a community-based epidemiologic study of urologic symptoms and risk factors. BACH used a two-stage stratified cluster sampling design to recruit 5,506 adults aged 30-79 (2301 men, 3205 women; 1770 black, 1877 Hispanic, and 1859 white).

RESULTS

In bivariate analyses, most urologic and sexual symptoms were associated with type II diabetes, cardiac disease, hypertension, and depression. However, in multivariate models adjusting for all four illnesses, gender, race/ethnicity, age, alcohol intake, smoking, physical activity, and body mass index there were fewer significant associations. We found that all urologic symptoms were significantly related to at least one illness, with depression increasing the odds of all urologic and sexual symptoms studied.

CONCLUSIONS

Urinary tract specialists should consider factors outside the urinary tract that may be contributing to urologic symptoms. It remains unknown whether treatment of medical and psychological illnesses can result in meaningful improvement in urologic symptoms, or conversely, whether urinary tract symptoms can provide valuable insight into an individual's overall health status.